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La hidrogenación por transferencia organocatalizadora de las enonas cíclicas
Jamison B Tuttle1, Stéphane G Ouellet, David W C MacMillan
1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
Journal of the American Chemical Society
|September 28, 2006
Resumen
Este estudio introduce la primera hidrogenación de transferencia organocatalítica enantioselectiva de las enonas cíclicas. Una nueva estrategia de catálisis de iminio reduce eficientemente las cicloalquenonas sustituidas utilizando una fuente de hidrógeno barata.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Catalización asimétrica por catálisis asimétrica.
- Química verde es la química verde.
Sus antecedentes:
- Las enonas cíclicas son importantes intermediarios sintéticos.
- La reducción enantioselectiva es crucial para la síntesis de moléculas quirales.
- La organocatálisis ofrece un enfoque libre de metales para la síntesis asimétrica.
Objetivo del estudio:
- Desarrollar la primera hidrogenación de transferencia organocatalítica enantioselectiva de las enonas cíclicas.
- Establecer una nueva estrategia de catálisis de iminio para la reducción asimétrica.
- Para sintetizar cetonas cíclicas beta-esterogénicas a partir de cetonas cíclicas alfa, beta-insaturadas sustituidas.
Principales métodos:
- Se utilizó la catálisis del iminio con imidazolidinonona 4 como catalizador asimétrico.
- Empleó el éster tert-butilo Hantzsch como una fuente de hidrógeno barata.
- Aplicó la metodología a sistemas de enones cíclicos de cinco, seis y siete miembros.
Principales resultados:
- Se logró con éxito la primera hidrogenación de transferencia organocatalítica enantioselectiva de enonas cíclicas.
- Demostró la amplia aplicabilidad del catalizador 4 a varios sustratos de enonas cíclicas.
- Cetonas cíclicas beta-esterogénicas generadas con alta enantioselectividad.
- Confirmó que el sentido de la inducción asimétrica se alinea con los modelos estereoquímicos establecidos.
Conclusiones:
- Desarrolló un nuevo y eficiente método organocatalítico para la reducción enantioselectiva de enonas cíclicas.
- La estrategia de catálisis del iminio proporciona una herramienta valiosa para acceder a las cetonas cíclicas quirales.
- El catalizador 4 muestra un amplio alcance de sustrato y resultados estereoquímicos predecibles.
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